The present invention relates, in general, to the field of photography and, more specifically, to photographic apparatus having manually operable dual actuators for facilitating sequential actuation of two different modes of apparatus operation.
The present invention is directed to improvements in photographic apparatus of the type generally disclosed in commonly-assigned copending applications: Ser. No. 54,598, entitled "Camera With Folding Flash Unit", filed July 3, 1979, by Bruce K. Johnson and George D. Whiteside; and Ser. No. 54,652, entitled "Camera With Telescoping Dual Actuators", filed July 3, 1979, by Carl W. Davis and Joseph E. Murray, Jr.; respectively. These cameras essentially include an electronic strobe-type flash unit powered by a battery which battery also powers the camera's electrical system. To prevent the battery's power delivery rate being exceeded so as to minimize its power drain and to prevent actuation of an exposure cycle before the flash is fully charged when it is desired to fire the latter, a sequential actuating system is provided. Such a system operates essentially to charge the flash unit storage capacitor immediately preceding the film exposure and processing cycle.
For instance, the approach taken in the aforenoted application Ser. No. 54,598 provides sequential actuation. This is, in part, accomplished by a dual actuator housed in an elongated actuator housing formed on one side of the camera. Extending from the actuator housing towards the camera user is a first actuator push button and longitudinally opposed therefrom is a forwardly facing second actuator button. In use, the first actuator push button is pushed forwardly for causing closing of an internal electrical switch. Closing of this switch allows the film pack battery to charge a flash unit capacitor. When charging is complete, as indicated by a visual signal in the viewfinder, the user pushes rearwardly on the second button. This latter movement causes an internal slider arrangement to effectively close a second internal electrical switch for initiating an automatic cycle of camera operation including film exposure with supplemental artificial illumination provided by the charged flash unit. This system works satisfactorily. There is, however, potential for problems.
For example, it might be somewhat awkward for the user to refrain from pushing rearwardly on the second forward facing push button while simultaneously with his second finger pushing forwardly with his thumb on the rearwardly facing first actuator push button. As a consequence thereof, inadvertent actuation of the exposure cycle could arise.
In anticipation of a user inadvertently operating the actuators in the wrong sequence, additional logic circuitry would be necessary for electrically blocking out an exposure start signal which is produced by operation of the second actuator push button. However, use of additional logic circuitry denies the user the option of initiating an exposure cycle of camera operation exclusive of the flash firing. This would be a problem whenever it is desired to, for example, take an exposure through a glass window wherein it is not desired to fire the flash unit. Additionally, battery drainage is a potential problem because of the absence of an inhibiting circuit for preventing inadvertent operation of a flash charge actuator when the camera is not being used.
The approach taken in copending U.S. patent application Ser. No. 54,652 overcomes the aforenoted potential for problems by eliminating the forward and aft placement of the first and second actuators as well as allowing the bypassing of the flash charging actuator when directly initiating an automatic cycle of camera operation. As described in this application, a dual actuating telescoping push button arrangement is provided. Specifically, a small forward inner button is initially depressed for effecting strobe charging. Thereafter, the photographer presses an outer button without releasing the inner button. The automatic cycle of camera operation is initiated upon the outer button effecting contact with an internal switch in the camera. While the foregoing approach successfully eliminates many of the potential problems associated with the foregoing described unit, there nevertheless exists a potential problem in that a user may inadvertently press the wrong button.
Other examples of cameras having dual actuators of the general type noted are referred to in commonly-assigned U.S. Pat. Nos. 4,001,640 and 4,085,414. It should be noted, however, that use of these dual actuators are somewhat awkward and their structure is not compatible with the noted internal slider switching arrangements of the foregoing cameras. This slider switching arrangement has proven it to be an extremely reliable device in, for example, the Pronto! and One Step cameras manufactured by the Polaroid Corporation, Cambridge, Mass.